U.S. patent application number 13/807136 was filed with the patent office on 2013-04-25 for method of removing metal carbonyls from gaseous streams and metal carbonyl sorbent.
This patent application is currently assigned to Haldor Topsoe A/S. The applicant listed for this patent is Pablo Beato, Poul Erik Hojlund Nielsen. Invention is credited to Pablo Beato, Poul Erik Hojlund Nielsen.
Application Number | 20130098243 13/807136 |
Document ID | / |
Family ID | 44461921 |
Filed Date | 2013-04-25 |
United States Patent
Application |
20130098243 |
Kind Code |
A1 |
Beato; Pablo ; et
al. |
April 25, 2013 |
METHOD OF REMOVING METAL CARBONYLS FROM GASEOUS STREAMS AND METAL
CARBONYL SORBENT
Abstract
Method of removing metal carbonyls from a gaseous stream
comprising contacting the metal carbonyl containing gaseous stream
at elevated temperature with a particulate sorbent comprising
modified copper aluminum spinel, wherein the copper aluminium
spinel has been modified by a thermal treatment in a reducing
atmosphere and a particulate sorbent for use in a method comprising
a copper aluminium spinel being modified by thermal treatment in a
reducing atmosphere at a temperature of between 250 and 500.degree.
C.
Inventors: |
Beato; Pablo; (Copenhagen S,
DK) ; Nielsen; Poul Erik Hojlund; (Fredensborg,
DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Beato; Pablo
Nielsen; Poul Erik Hojlund |
Copenhagen S
Fredensborg |
|
DK
DK |
|
|
Assignee: |
Haldor Topsoe A/S
Kgs.Lynby
DK
|
Family ID: |
44461921 |
Appl. No.: |
13/807136 |
Filed: |
May 17, 2011 |
PCT Filed: |
May 17, 2011 |
PCT NO: |
PCT/EP2011/002446 |
371 Date: |
December 27, 2012 |
Current U.S.
Class: |
95/133 ;
423/600 |
Current CPC
Class: |
B01D 2256/16 20130101;
B01D 53/14 20130101; B01D 2256/20 20130101; B01J 20/08 20130101;
B01J 37/18 20130101; B01D 2255/2092 20130101; B01D 53/64 20130101;
B01J 20/06 20130101; B01D 2257/60 20130101; B01J 37/08 20130101;
B01D 2253/1124 20130101; B01D 2255/20761 20130101; B01J 20/3078
20130101; B01J 37/031 20130101; B01D 2255/405 20130101; B01J 23/72
20130101; B01J 20/0237 20130101; B01D 53/02 20130101; B01J 37/0045
20130101; B01J 21/04 20130101; B01J 23/005 20130101 |
Class at
Publication: |
95/133 ;
423/600 |
International
Class: |
B01J 20/08 20060101
B01J020/08; B01D 53/14 20060101 B01D053/14 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 5, 2010 |
DK |
PA 201000591 |
Claims
1. Method of removing metal carbonyls from a gaseous stream
comprising: contacting the metal carbonyl containing gaseous stream
at elevated temperature with a particulate sorbent comprising
modified copper aluminum spinel, wherein the copper aluminium
spinel has been modified by a thermal treatment in a reducing
atmosphere.
2. Method of claim 1, wherein the thermal treatment includes
heating of the copper aluminum spinel at a temperature of between
250 to 500.sup.SC.
3. Method of claim 1, where the reducing atmosphere is synthesis
gas, optionally diluted with an inert gas.
4. Method of claim 1, wherein the gaseous stream contains carbon
monoxide.
5. Method of claim 1, wherein the particulate sorbent further
comprises copper oxide in addition to the copper aluminum spinel
prior to the modification.
6. Method of claim 1, wherein the particulate sorbent further
comprises copper in excess to the amount being present in the
copper aluminum spinel.
7. A particulate sorbent for use in a method of claim 1 comprising
a copper aluminium spinel being modified by thermal treatment in a
reducing atmosphere at a temperature of between 250 and
500.sup.2C.
8. A particulate sorbent, having an X-ray powder diffraction
pattern as shown in FIG. 1b.
Description
[0001] The present invention relates to a method for the removal of
metal carbonyl compounds from a gaseous stream by contacting the
stream with a solid sorbent. More particularly, the invention
provides a method by which metal carbonyls being present as
impurities in a gaseous stream are removed and passivated by
contact with a modified copper aluminium spinel sorbent at elevated
temperatures.
[0002] Chemical processes that use gas mixtures with a high CO
partial pressure at elevated temperature focus the problem of metal
carbonyl formation via reactions of CO with tubings and other steel
or iron construction materials. Metal carbonyls, in particular
Ni(CO).sub.4 and Fe(CO).sub.5 can act as severe poison for several
catalyst systems that convert gas to more valuable products. In the
case of Fe(CO).sub.5 the deactivation arises from the formation of
a Fe-carbide phase, which consequently acts as a Fischer-Tropsch
catalyst and provokes waxing of the catalyst and thereby hindering
the access to the active sites. Due to the increasing trend of
using coal and biomass as source for synthesis gas newly designed
synthesis gas conversion processes need to be effectively protected
against metal carbonyls.
[0003] We have found that when modifying copper aluminium spinel by
treatment in a reducing atmosphere at elevated temperatures
provides an effective sorbent material for the removal of carbonyl
compounds from a gaseous stream.
[0004] Pursuant to this finding this invention provides a method of
removing metal carbonyls from a gaseous stream comprising
contacting the metal carbonyl containing gaseous stream with a
particulate sorbent comprising modified copper aluminum spinel,
wherein the copper aluminium spinel has been modified by a thermal
treatment in a reducing atmosphere.
[0005] Copper aluminum spinels are per se known compounds and the
preparation of copper aluminum spinel is described in the art e.g.
Z.Phys.Chem., 141 (1984), 101-103. An essential step of the method
according to the invention is the modification of copper aluminum
spinel.
[0006] Preferably, the particulate sorbent further comprises copper
oxide in excess to the amount being present in the copper aluminum
spinel prior to modification.
[0007] A typical preparation method comprises co-precipitation of
copper and aluminum salts and calcination in air at a temperature
of between 700.degree. C. and 900.degree. C. to form crystals with
the spinel structure.
[0008] An essential step of the method according to the invention
is the modification of copper aluminum spinel. To this end the
spinel prepared as for instance mentioned above is subjected to
thermal treatment in a reducing atmosphere.
[0009] The length of the treatment depends on the temperature and
composition of the reducing atmosphere.
[0010] Reducing atmospheres being useful in the modification of the
copper aluminum spinel are hydrogen or gas mixtures containing
hydrogen and carbon monoxide, such as synthesis gas diluted with an
inert gas.
[0011] A preferred reducing atmosphere consists of 5 vol. % carbon
monoxide, 5 vol. % carbon dioxide and 90 vol. % hydrogen. A further
preferred reducing atmosphere contains about 0.5 vol. % carbon
monoxide, about 5 vol. % carbon dioxide and about 5 vol. % hydrogen
in nitrogen.
[0012] Typically, the temperature employed in the thermal treatment
step will be between 250 and 500.degree. C.
[0013] The thus modified sorbent is effective at temperatures at
150 to 300.degree. C. Therefore it will be possible in a number of
chemical reactions for the conversion of a gaseous reactant stream
to place the absorbent directly on top of a catalyst bed instead of
having a separate guard reactor, which would also imply a cooling
and/or heating step of the gaseous stream prior to contact with the
catalyst.
[0014] As already introductorily mentioned, the method according
the invention is particular useful in the treatment of carbon
monoxide containing gaseous streams, such as synthesis gas. By
means of the modified copper aluminum sorbent, the content of metal
carbonyls in such gases can be removed to the low ppb level,
typically below 1 ppb.
[0015] The invention provides additionally a particular sorbent
being useful in the above disclosed method.
[0016] The sorbent according to the invention comprises a copper
aluminium spinel being modified by calcination in a reducing
atmosphere at a temperature of between 250 to 500.degree. C.
[0017] FIG. 1 shows the XRD analysis of the Al.sub.2CuO.sub.4
sorbent calcined at 835.degree. C. (FIG. 1a) and the resulting
activated sorbent after treatment in 3% H.sub.2 in Ar at
350.degree. C. (FIG. 1b). The XRD pattern of the calcined
Al.sub.2CuO.sub.4 sorbent can be fitted by the Rietvield refinement
method to a composition of 93.2 wt % Al.sub.2CuO.sub.4 (PDF
04-011-8984) and 6.8 wt % CuO (PDF 04-012-7238). After the
activation in reducing atmosphere the XRD pattern changes visibly
(FIG. 1b). A Rietvield refinement results in 14.4 wt % of remaining
Al.sub.2CuO.sub.4 (PDF 04-011-8984) spinel phase and 62.7 wt % of a
new spinel type phase which was best fitted with
.gamma.-Al.sub.2.67O.sub.4 (PDF 04-007-2479). The activated sorbent
further contains 16.8 wt % Cu metal and 6.1 wt % CuO (PDF
04-012-7238). The lattice parameters and crystal sizes of all
refined structures are given in Table 1-2.
TABLE-US-00001 TABLE 1 Relevant parameters for calcined sorbent
Relative Space Refined PDF amount group Lattice Compound number [wt
%] (No.) constants [.ANG.] Al.sub.2CuO.sub.4 04-011- 93.2 Fd-3m
8.0766 8984 (227) CuO 04-012- 6.8 C12/c1 a = 4.6930; 7238 (15) b =
3.4201; c = 5.1294
TABLE-US-00002 TABLE 2 Relevant parameters for activated sorbent
Relative Space Refined PDF amount group Lattice Compound number [wt
%] (No.) constants [.ANG.] Al.sub.2CuO.sub.4 04-011- 14.4 Fd-3m
8.0250 8984 (227) CuO 04-012- 6.1 C12/c1 a = 4.6836; 7238 (15) b =
3.4231; c = 5.1265 ".gamma.-Al.sub.2,.sub.67O.sub.4" 04-007- 62.7
Fd-3m 7.9600 2479 (227) Cu 04-001- 16.8 Fm-3m 3.6176 0092 (225)
EXAMPLES
Example 1
Preparation of a Copper Aluminum Spinel for Use in the
Invention
[0018] In a precipitation tank 78.4 kg of copper nitrate solution
with 8.1% Cu (100 mol Cu) is added to 360 l water. The thus
prepared solution is precipitated at room temperature with 47.3 kg
potassium-aluminate (11.4% Al or 200 mol Al). The pH value of the
forming slurry is currently adjusted to 8.5 by conc. nitric acid.
45 kg KHCO.sub.3 solution (11.1% KHCO.sub.3) are added to the
slurry and the slurry is allowed to mature after heating to
80.degree. C. After washing, the slurry is spray dried and calcined
at 800.degree. C. to form CuAl.sub.2O.sub.4.
Example 2
Modification of the Copper Aluminum Spinel
[0019] The copper aluminum spinel prepared in Example 1 is modified
in a reducing atmosphere consisting of 0.5 vol. % CO, 5 vol. % CO2
and 5 vol. % H2 in nitrogen at a space velocity of 4000 Nl/h*kg at
380.degree. C. for about 3 hours.
[0020] The thus modified copper aluminum spinel has an X-ray powder
diffraction pattern as shown in FIG. 1 in the drawings and
summarized in Table 1 below.
Example 3
Sorption Test of the Modified Copper Aluminum Spinel Sorbent
Prepared in Example 2 in the Removal of Iron Carbonyl
[0021] The test is performed in Cu-lined steel reactor tubes of 50
cm length and an inner diameter of 7 mm. The standard reaction
conditions are conducted with a synthesis gas containing 5%
CO.sub.2, 3% Ar, 26% CO, (H.sub.2 balanced) at 210.degree. C., 75
barg and a flow of 50 Nl/h.
[0022] An iron wire of 10 cm length is placed in the top part of
the reactor to produce iron carbonyls when contacted with the
synthesis gas. For the experiments the iron wire was acid-etched to
give a relatively stable amount of iron carbonyls in the range of
15 to 20 ppb. Before loading, the wire is rolled up to a spherical
shape (diameter about the size of the reactors' inner diameter).
The wire is then degreased by dipping it for 30 seconds into 25 ml
of acetone and in continuation etched for 10 minutes in 25 ml of
10% HNO.sub.3. After etching, the wire is rinsed with de-ionized
water and pat dried on a piece of paper. Below the iron wire, a
stacked bed (separated by glass wool) of five layers of the sorbent
were placed. Each layer contained 400 mg with a particle size of
300 to 600 .mu.m. The stacked sorbent bed pellets A1 to A5 are
followed by a string of 10 pellets of a Cu containing methanol
catalyst (in total approx. 2 g). Each experiment is typically run
for 6 to 7 days. During a run the methanol activity of the catalyst
is measured by means of GC gas phase analysis. After cooling in
N.sub.2 and passivation, the sorbent and the catalyst are taken out
of the reactor pellet- and layer-wise, in the same order as
introduced. Each sorbent zone and a sample of a fresh sorbent are
analysed by ICP-MS to determine the Fe-content and total C-content.
The methanol catalyst pellets C1-3 and C8-10 (1=top) are separately
sent to Fe analysis, while pellets C4-7 were mixed and extracted
with a mixture of isooctane and carbon disulphide to analyse the
exact carbon composition via GC-MS. The methanol condensate was
analysed for Fe to check for any Fe slip. From the analysis results
of all samples, the total Fe concentration in the feed was
determined and an absorption profile along the reactor established
(see Table 3).
TABLE-US-00003 TABLE 3 Fe carbonyl guard test at 5% CO.sub.2, 3%
Ar, 26% CO, 66% H.sub.2 at 210.degree. C., 75 barg and a flow of 50
Nl/h, time on stream 792 h. Conc. of Fe(CO).sub.5 in the feed = 16
ppb Absorber layer/ catalyst pellet (from top) A1 A2 A3 A4 A5 C1 C2
C3 C4-C7 C8 C9 C10 Fe content 2930 a 815 a 95 a 65 a 75 a 30 b 20 b
20 b 20 b 20 b -- 20 b (wt ppm) C content 0.42 0.37 0.35 0.34 0.34
6.27 (wt %) Removal efficiency 97.9 2.1 (%) a initial Fe content
was 65 wt ppm; b initial Fe content was 20 wt ppm.
* * * * *